Joined: 28 Mar 2005 Posts: 1509 Location: Chicago, IL
What is a check point : A point in the execution of program when, the changes made to the database are considered complete and accurate.
Once checkpointed, the changes made are not reversible.
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which situation the checkpoint will be used
To establish intermediate checkpoints it is used. By default, the Beginning as well as the normal end of a Batch program are checkpoints.
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How the check point used in imsdb pgm?\
HOW: By issuing a CHKP call, while a program is being executed.
CHKP call causes all the databases changes made since the last checkpoint to be permanently committed to the physical database thereby making a Backout impossible.
Checkpoint are used basically to save the data that is processed correctly.
In cases where u have a large number of records to be processed u really dont know if all the records have the right info to pass thru there could be cases where an abend can occur.
In such cases u do not want to loose data that is already processed .so u place a checkpoint saying after x records place a checkpoint and code the program in such a way that if it the first run of the program just start normally else restart from the last checkpoint taken...
In short checkpoint is a systematic way of abending the program in case one happens so u dont loose any data.
